Freenom gives you the opportunity to register and in the future, and free of charge, to renew the 5 types of free top-level domains: .tk .ml .ga .cf .gq
If you want to have more reliable access to your domain, then you are advised to buy it (and desirable in another registrar).
The registrar Freenom though gives free access to the domains but also often takes it back without explanation. But if you follow all the rules and recommendations that will come to you from the registrar, then you may be able to get up to the domain for a long time.
But these domains are equally well suited for use with fake email.
We go to the site freenom.com and look for an available domain.
If the domain is free then we can register it.
If you are not registered then you can use fake email it for further registration, but if you want to continue to access this domain then we recommend you use a verified own account.
For fast filling in the registration form we use name-fake.com
Add MX server according to the instructions: https://emailfake.com/blog/new-fake-email-domain
Save and wait until new settings come into effect
Now we can use the new domain here: https://emailfake.com/drthst4wsw.tk
If nothing happens for a long time, you can check the settings here: https://emailfake.com/blog/fake-email-domain-debugger/drthst4wsw.tk